PERROR(3C) Standard C Library Functions PERROR(3C)
NAME
perror, errno - print system error messages
SYNOPSIS
#include <stdio.h>
void perror(
const char *s)
#include <errno.h>
int errno;
DESCRIPTION
The
perror() function produces a message on the standard error output
(file descriptor 2) describing the last error encountered during a call
to a system or library function. The argument string
s is printed,
followed by a colon and a blank, followed by the message and a
NEWLINE character. If
s is a null pointer or points to a null string, the colon
is not printed. The argument string should include the name of the
program that incurred the error. The error number is taken from the
external variable
errno, which is set when errors occur but not cleared
when non-erroneous calls are made. See
Intro(2).
In the case of multithreaded applications, the
-mt option must be
specified on the command line at compilation time (see
threads(7)). When
the
-mt option is specified,
errno becomes a macro that enables each
thread to have its own
errno. This
errno macro can be used on either side
of the assignment as though it were a variable.
USAGE
Messages printed from this function are in the native language specified
by the
LC_MESSAGES locale category. See
setlocale(3C).
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
Intro(2),
fmtmsg(3C),
gettext(3C),
setlocale(3C),
strerror(3C),
attributes(7),
standards(7),
threads(7) July 12, 2007
PERROR(3C)